Search

BackgroundPrader-Willi syndrome (PWS) is an imprinting disorder caused by the absence of paternal expressed genes in the Prader-Willi critical region (PWCR) on chromosome 15q11.2-q13. Three molecular mechanisms have been known to cause PWS, including a deletion in the PWCR, uniparental disomy 15 and imprinting defects.ResultsWe report the first case of PWS associated with a single-nucleotide SNRPNvariant in a 10-year-old girl presenting with clinical features consistent with PWS, including infantile hypotonia and feeding difficulty, developmental delay with cognitive impairment, excessive eating with central obesity, sleep disturbances, skin picking and related behaviour issues. Whole-exome sequencing revealed a de novo mosaic nonsense variant of the SNRPNgene (c.73C>T, p.R25X) in 10% of DNA isolated from buccal cells and 19% of DNA from patient-derived lymphoblast cells. DNA methylation study did not detect an abnormal methylation pattern in the SNRPNlocus. Parental origin studies showed a paternal source of an intronic single-nucleotide polymorphism within the locus in proximity to the SNRPNvariant.ConclusionsThis is the first report that provides evidence of a de novo point mutation of paternal origin in SNRPNas a new disease-causing mechanism for PWS. This finding suggests that gene sequencing should be considered as part of the diagnostic workup in patients with clinical suspicion of PWS.

Background: Prader-Willi Syndrome (PWS) is a neurodevelopmental genomic imprinting disorder with lack of expression of genes inherited from the paternal chromosome 15q11-q13 region usually from paternal 15q11-q13 deletions (about 60%) or maternal uniparental disomy 15 or both 15s from the mother (about 35%). An imprinting center controls the expression of imprinted genes in the chromosome 15q11-q13 region. Key findings include infantile hypotonia, a poor suck, failure to thrive and hypogonadism/hypogenitalism. Short stature and small hands/feet due to growth and other hormone deficiencies, hyperphagia and marked obesity occur in early childhood, if uncontrolled. Cognitive and behavioral problems (tantrums, compulsions, compulsive skin picking) are common. Objective: Hyperphagia and obesity with related complications are major causes of morbidity and mortality in PWS. This report will describe an accurate diagnosis with determination of specific genetic subtypes, appropriate medical management and best practice treatment approaches. Methods and Results: An extensive literature review was undertaken related to genetics, clinical findings and laboratory testing, clinical and behavioral assessments and summary of updated health-related information addressing the importance of early PWS diagnosis and treatment. A searchable, bulleted and formatted list of topics is provided utilizing a Table of Contents approach for the clinical practitioner. Conclusion: Physicians and other health care providers can use this review with clinical, genetic and treatment summaries divided into sections pertinent in the context of clinical practice. Frequently asked questions by clinicians, families and other interested participants or providers will be addressed.

BackgroundPrader-Willi syndrome (PWS) is due to errors in genomic imprinting. PWS is recognised as the most common known genetic cause of life-threatening obesity. This report summarises the frequency and further characterises the PWS molecular classes and maternal age effects.MethodsHigh-resolution microarrays, comprehensive chromosome 15 genotyping and methylation-specific multiplex ligation probe amplification were used to describe and further characterise molecular classes of maternal disomy 15 (UPD15) considering maternal age.ResultsWe summarised genetic data from 510 individuals with PWS and 303 (60%) had the 15q11-q13 deletion; 185 (36%) with UPD15 and 22 (4%) with imprinting defects. We further characterised UPD15 findings into subclasses based on the presence (size, location) or absence of loss of heterozygosity (LOH). Additionally, significantly older mothers (mean age=32.5 years vs 27.7 years) were found in the UPD15 group (n=145) compared with the deletion subtype (n=200).ConclusionsWe report on molecular classes in PWS using advanced genomic technology in the largest cohort to date. LOH patterns in UPD15 may impact the risk of having a second genetic condition if the mother carries a recessive mutant allele in the isodisomic region on chromosome 15. The risk of UPD15 may also increase with maternal age.

IntroductionPrader-Willi syndrome (PWS) is a complex genetic disorder associated with three different genetic subtypes: deletion of the paternal copy of 15q11-q13, maternal UPD for chromosome 15 and imprinting defect. Patients are typically diagnosed because of neonatal hypotonia, dysmorphism and feeding difficulties; however, data on the prenatal features of PWS are limited.ObjectiveThe aim of the study was to identify and compare frequencies of prenatal and neonatal clinical features of PWS among the three genetic subtypes.MethodsData from 355 patients with PWS from the Rare Diseases Clinical Research Network PWS registry were used to analyse multiple maternal and neonatal factors collected during an 8-year multisite study.ResultsAmong our cohort of 355 patients with PWS (61% deletion, 36% UPD and 3% imprinting defect) 54% were born by caesarean section, 26% were born prematurely and 34% with a low birth weight (frequencies 32%, 9.6% and 8.1%, respectively, in the general population). Fetal movements were reported as decreased in 72%. All babies were hypotonic, and 99% had feeding difficulties. Low Apgar scores (<7) were noted in 17.7% and 5.6% of patients, respectively, compared with 1% and 1.4%, respectively, in the general population. Maternal age and pre-pregnancy weight were significantly higher in the UPD group (p=0.01 and <0.001, respectively).ConclusionWe found a higher rate of perinatal complications in PWS syndrome compared with the general population. No significant differences in the genetic subtypes were noted except for a higher maternal age and pre-pregnancy weight in the UPD subgroup

PurposePrader–Willi syndrome (PWS) is a complex genetic disorder characterized by hyperphagia and morbid obesity with increased cardiopulmonary and hyperphagia-related mortality. Survival trends in PWS were evaluated to assess the impact of modern interventions on mortality risk.MethodsThe Prader–Willi Syndrome Association (USA) 40-year mortality syndrome-specific database of 486 death reports was utilized to examine survival trends in PWS and cohort effects for recent deaths (years 2000–2015, N=331) relative to deaths prior to 2000 (N=94). Cox proportional hazards regression modeling was applied to generate log rank statistics and Kaplan–Meier curves examining sex, cause of death, and cohort.ResultsRisk for all-cause mortality in PWS was 1.5 (95% confidence interval (CI)=1.2–1.9) times higher for the Early than the Recent era cohort reflected in female cardiac failure (hazard ratio (HR)=1.8; 95% CI=1.3–2.6), pulmonary embolism (HR=6.1; 95% CI=1.7–22), and gastrointestinal-related (HR=3.2; 95% CI=1.1–7.4) causes. Accidental deaths in males increased in the Recent era cohort (HR=5.7; 95% CI=1.2–27.1), possibly due to enhanced weight management and mobility. Risk of death from respiratory failure was unchanged.ConclusionWe report measurable increases in survival effecting cardiovascular and gastrointestinal-related causes in PWS most likely attributable to earlier diagnosis and proactive interventions to prevent morbid obesity. More research is needed to address underlying vulnerability to respiratory failure, an unchanged mortality risk in PWS.

Prader–Willi syndrome (PWS) is a complex genetic disorder characterized by hyperphagia and morbid obesity with increased cardiopulmonary and hyperphagia-related mortality. Survival trends in PWS were evaluated to assess the impact of modern interventions on mortality risk.

Mowat-Wilson syndrome is a rare genetic condition characterized by intellectual disability, structural anomalies, and dysmorphic features. It is caused by haploinsufficiency of the ZEB2gene in chromosome 2q22.3. Over 180 distinct mutations in ZEB2have been reported, including nonsense and missense point mutations, deletions, and large chromosomal rearrangements. We report on a 14-year-old female with a clinical diagnosis of Mowat-Wilson syndrome. Chromosomal microarray identified a novel de novo 69-kb duplication containing exons 1 and 2 of the ZEB2gene. Sequence analysis identified no other variants in this gene. This is the first report of a partial duplication of the ZEB2gene resulting in Mowat-Wilson syndrome.

Prader–Willi syndrome (PWS) is a neurodevelopmental genetic disorder characterized by intellectual disabilities and insatiable appetite with compulsive eating leading to severe obesity with detrimental health consequences. Transcranial direct current stimulation (tDCS) has been shown to modulate decision‐making and cue‐induced food craving in healthy adults. We conducted a pilot double blind, sham‐controlled, multicenter study of tDCS modulation of food drive and craving in 10 adult PWS participants, 11 adult obese (OB) and 11 adult healthy‐weight control (HWC) subjects. PWS and OB subjects received five consecutive daily sessions of active or sham tDCS over the right dorsolateral prefrontal cortex (DLPFC), while HWC received a single sham and active tDCS in a crossover design. Standardized psychometric instruments assessed food craving, drive and hyperphagia by self‐report and caregiver assessment over 30 days. Robust baseline differences were observed in severity scores for the Three‐Factor Eating Questionnaire (TFEQ) and Dykens Hyperphagia Questionnaire (DHQ) for PWS compared to HWC while obese participants were more similar to HWC. Active tDCS stimulation in PWS was associated with a significant change from baseline in TFEQ Disinhibition (Factor II) (Ƶ = 1.9, P< 0.05, 30 days) and Total Scores (Ƶ = 2.3, P< 0.02, 30 days), and participant ratings of the DHQ Severity (Ƶ = 1.8, P< 0.06, 5 days) and Total Scores (Ƶ = 1.9, P< 0.05, 15 days). These findings support sustained neuromodulatory effects and efficacy of tDCS to reduce food drive and behaviors impacting hyperphagia in PWS. Transcranial direct current stimulation may represent a straight‐forward, low risk and low cost method to improve care, management and quality of life in PWS. © 2015 Wiley Periodicals, Inc.

A large body of genetic data from schizophrenia‐related research has identified an assortment of genes and disturbed pathways supporting involvement of complex genetic components for schizophrenia spectrum and other psychotic disorders. Advances in genetic technology and expanding studies with searchable genomic databases have led to multiple published reports, allowing us to compile a master list of known, clinically relevant, or susceptibility genes contributing to schizophrenia. We searched key words related to schizophrenia and genetics from peer‐reviewed medical literature sources, authoritative public access psychiatric websites and genomic databases dedicated to gene discovery and characterization of schizophrenia. Our list of 560 genes were arranged in alphabetical order in tabular form with gene symbols placed on high‐resolution human chromosome ideograms. Genome wide pathway analysis using GeneAnalytics was carried out on the resulting list of genes to assess the underlying genetic architecture for schizophrenia. Recognized genes of clinical relevance, susceptibility or causation impact a broad range of biological pathways and mechanisms including ion channels (e.g., CACNA1B, CACNA1C, CACNA1H), metabolism (e.g., CYP1A2, CYP2C19, CYP2D6), multiple targets of neurotransmitter pathways impacting dopamine, GABA, glutamate, and serotonin function, brain development (e.g., NRG1, RELN), signaling peptides (e.g., PIK3CA, PIK4CA) and immune function (e.g., HLA‐DRB1, HLA‐DQA1) and interleukins (e.g., IL1A, IL10, IL6). This summary will enable clinical and laboratory geneticists, genetic counselors, and other clinicians to access convenient pictorial images of the distribution and location of contributing genes to inform diagnosis and gene‐based treatment as well as provide risk estimates for genetic counseling of families with affected relatives. © 2015 Wiley Periodicals, Inc.

We report on a 15-year-old male with the 3q29 microdeletion syndrome and summarize the medical literature. He had intellectual disability, autism spectrum disorder, anxiety, obsessive compulsive tendencies, speech delay, delayed walking, a hypernasal voice, gait abnormalities, chronic constipation, gastroesophageal reflux disorder, urinary voiding dysfunction, abnormal skin pigmentation, and dysmorphic features. We present a review of the literature for the 3q29 microdeletion syndrome by comparing both the phenotype and the genetic defects in reported cases. Of the 38 previously reported cases with deletion size information, the most common chromosome deletion was 1.6 Mb in size including ∼30 genes. This emerging microdeletion syndrome is characterized by intellectual disability, speech delay, behavioral problems, craniofacial dysmorphism, and musculoskeletal abnormalities.